Arnold Schwarzenegger was facing fresh questions about his ethical record as governor of California, as he disclosed it had cost him $200m (€150m) of savings and lost earnings to stay in the job.

The former actor, who has indicated that he plans to become an international environmental advocate, told a newspaper in his native Austria that politics has cost him "more than $200 million".

The 63-year-old told Krone the total included campaign funding, expenses and loss of earnings from Hollywood films he could have made. He added: "But I'm not sorry. It was more than worth it."

As he stepped down earlier this month after seven years, Mr Schwarzenegger cut the prison sentence of Esteban Nuñez, the son of a political ally, who was jailed for 16 years after being involved in a murder.

He said he made the decision because Nuñez had not delivered the fatal blow and had no prior criminal record. However, state records show that he made the opposite decision in similar cases.

In 2009, he reversed the California parole board's decision to free 29 inmates comparably involved in crimes that left people dead. Eleven of these had no previous criminal convictions.

He said some of these prisoners had demonstrated "callous disregard for human suffering" by fleeing the scene of their crimes and leaving their victims to die.

Nuñez and a group of friends fled after drunkenly attacking a group of strangers in San Diego after being blocked from a party in 2008. One man was fatally stabbed. Nuñez stabbed another in the stomach.

Mr Schwarzenegger has declined to elaborate further on his decision to commute Nuñez's sentence to seven years.

Mr Schwarzenegger, who put tackling climate change at the centre of his agenda, regularly commuted to work in Sacramento in his private jet, at a personal cost of hundreds of thousands of dollars.